Investigation of beam acceleration and extraction on a stellatron

The stellatron accelerator of the University of California at Irvine (UCI) [Phys. Fluids B2, 3149 (1990)] was modified to accommodate beam extraction. The magnetic field coils were reconstructed to adapt an extraction port. A fiberglass-graphite-epoxy chamber replaced the glass chamber that cracked frequently during the previous experiment. Improvement in the magnetic field configuration has significantly reduced the current loss during acceleration. A 1.1 kA, 12 MeV electron beam was generated by initially forming a 1.2 kA beam with plasma start-up. The beam radius was 5–7 mm. Beam extraction was performed with two auxiliary pulsed current coils and up to 15% of the beam was extracted from the chamber. The extraction process was analyzed by computational orbit simulations.